Improvement in barometers



R. M. LOWNE.

Barometer.

Nb. 200,739. Patented Feb. 26,1878.

(Ur/ Med W179. (Saab/n2 NJ'ETERQ FHOTC LTHOGRAFH WASHINGTON D C UNITEDSTATES PATENT QFFICE.

ROBERT MANN LOWN E, OF EAST END, FINGHLEY, ENGLAND, ASSIGNOR TO JOSEPHGALL, OF NEW YORK, N. Y.

IMPROVEMENT IN BAROMETERS.

Specification forming part of Letters Patent No. 200,739, dated February26, 1878; application filed August 16, 1877.

To all whom it may concern:

Be it known that I, ROBERT MANN LOWNE, of East End, Finchley, in thecounty of Mid dlesex, England, have invented new and useful Improvementsin Barometers, of which the following is a specification:

The invention has for its object improvements in barometers; and relatesto means for rendering them self-compensating for differences oftemperature, and at the same time providing them with an open and fixedscale.

The instrument devised by me is very simple in construction and consistsin a tube open at one end to the atmosphere, and continued downward tothe bottom, where it is bent round to form an inverted goose-neck, thetop of which expands into a bulb. This tube is then continued upwardtherefrom, in a line parallel to the open portion of the tube, until itterminates in anotherbulb at the other end.

This instrument thus constructed is somewhat of the character of thatclass of barometerknown as the sympiesom eter, but instead of allowingthe height of the indicating fluid to be varied by any variation oftemperature acting upon and expanding or contracting the air in theair-bulb, the fluid in the lower bulb is also aflected by changes oftemperature.

In preparing my thermometer for use, air is allowed to enter the upperbulb and that portion of the tube immediately below it constituting thegage-tube. Then oil or other indicating fluid is poured down the opentube until it fills, or nearly fills, the lower bulb. A sufficientquantity of mercury or other heavy fluid is then poured in until itrises to the top of the inverted goose-neck, and covers a portion of thebottom of the lower bulb, the column of mercury or other heavy fluidthus acting to support the indicating fluid. The scale is fixed betweenthe two bulbs.

By this construction of barometerany change of temperature which, in theordinary construction of sympiesometer, would cause the air in the bulbto force down the column of fluid, also acts upon the fluid in the lowerbulb or chamber to expand it, and thereby causes such fluid to force themercury or other heavy fluid higher in the open tube, to compensate forthe greater pressure of air in the air-bulb.

If it be desired to prevent differences and rapid changes of temperaturefrom unequally affecting the contents of the two bulbs, the air-bulb maybe inclosed in another bulb or chamber surrounding the same, and leavinga space between the two bulbs, which space may be filled with spirit orother fluid.

In the drawings, Figure 1 represents a frontelevation of a small-sizebarometerconstructed according to my invention, and Fig. 2 is a sectionthrough the bulbs and tubes of the same.

a, represents that portion of the verticallybent tube which forms thegage-tube. This tube terminates at its upper end in an airbulb, b, andhas at its lower end a bulb, c, to contain any suitable indicatingfluid. The tube is continued downward from said bulb c in the form of aninverted goose-neck, which terminates in that portion of theverticallybent tube cl parallel to a and open to the atmosphere.

The bulb c is filled with oil or other fluid, which rises up the gageportion of the tube a, and the other portion, d, of the tube is filledup to the point cl with mercury or other heavy fluid, which rises up theinverted goose-neck to the bulb c.

1 claim- Thebarometer herein described, having gagetube a,compressed-air bulb b, fluid-reservoir c, and mercury-tube d, the latterbeing open at its upper end to the atmosphere, its lower part forming aninverted goose-neck,terminating a short distance above the bottom in thereservoir 0, the whole being formed out of the material of a continuoustube bent to form two vertical legs, substantially as set forth.

R. M. LOWNE.

Witnesses:

B. J. B. MILLs, O. M. WHITE, Both of 23 Southampton Buildings, London.

